Exhaust tube arrangement in flat disc press electron discharge devices



, June 1943- H. J. LEMMENS arm. 08

EXHAUST TUBE ARRANGEMENT IN FLAT DISC PRESS ELECTRON DISCHARGE DEVICES Filed larch 23, 1943 FIGJ FIG. 2

H.J. LEMMENS; J.L.H.JONKER8 O.L. VAN STEENIS BMW AGENT Patented June 1, 1948 EXHAUST TUBE ARRANGEMENT FLAT DISC PRESS ELECTRON DISCHARGE DE- VICES Hendricus Johannes Lemmens, Johan Lodewijk Hendrik Jonker, and Otto Louis van Steenis, Eindhoven, Netherlands, assignors to Hartford National Bank and Trust Company, Hartford, Y

Conn., as trustee Application March 23, 1943, Serial No. 480,188

In the Netherlands August 10, 1940 a Section 1, Public Law 690, August 8, 1946 Patent expires August 10, 1960 6 Claims. (Cl. 250-275) 1 This invention relates to an electric discharge tube, particularly to the type of tube which is closed by a substantially flat or disc stem with an exhaust tube.

In discharge tubes which have the exhaust tube in a disc stem it has been found that the outwardly projecting end of the exhaust tube should be surrounded by a shield for protection, of both metal and glass exhaust tubes.

In a discharge tube according to the invention which is closed by a substantially flat or disc stem comprising a flat header carrying the exhaust tube the latter is shielded and protected by a tubular member such as a metal sleeve or cap, which is fastened to a metal thimble projecting from the outer side of the header. The tubular sleeve or shield may be fastened to the projecting end of the thimble by clamping, soldering or welding, the weld being located on a portion of the thimble which projects to a greater distance from the tube than the supply conductors of the electrodes. The thimble which carries the metal shield or cap made integral with a metal header by forming the central portion of the header into an outwardly projecting cylindrical boss, and with a glass or ceramic header by sealing or molding the thimble into the header simultaneously with the making of the stem. In the case of glass and ceramic stems the thimble extends through the header and acts as an electrostatic shield between the supply conductors and also between the portions of the conductors embedded in the glass or ceramic.

The invention will be set out more fully by reference to the accompanying drawing in which Figure 1 shows, by way of example, one form of construction of a portion in section of a glass stem of a discharge tube according to the invention, and Figure 2 shows in section a portion of a metal stem.

In the drawing, I designates the glass exhaust tube of the tube sealed in a glass disc header 2 and in Fig. 2 a metal exhaust tube in a metal header 3. In the form of construction shown in Fig. 1 the exhaust tube projects from the outer side of the header through a tubular metal thimble 4 which extends through the stem and projects from the outer side of the header. This thimble has fastened to it a metal shielding sleeve or cap 5, which is preferably made in the form of a locating member, and fastened in some manner or other to the thimble 4, preferably being telescoped over the projecting end of the thimble and fastened to it at the points designated 6, for example by clamping, soldering, or, if the points 6 are sufliciently remote from the stem, by welding.

In Fig. 2 a shielding sleeve or cap 1 is fastened in a similar manner to a thimble or tubular boss 8 which is integral with and projects from the metal header, and is preferably formed by stamping it out of the central portion of the header.

The tubular thimble 4 is concentric with and surrounds the exhaust tube l which communicates with the interior of the discharge tube. The

thimble which is hermetically sealed into and ex-.

tends through the stem with its projecting outer end telescoped into the metal sleeve or cap forms an effective electrostatic shield between the supply conductors (not shown) and also a rigid and effective support to which the shielding sleeve or cap may be attached by soldering or welding after the discharge tube has been exhausted and without injury to the tube.

We claim:

1. An electric discharge tube having an envelope closed at one end with a fiat disc-shaped header, a round thimble extending outwardly from the surface of the header, an exhaust tube concentric with and extending through said thimble and communicating with said envelope,

and a tubular bushing telescoped over and secured to said thimble to mechanically protect said exhaust tube.

2. An electric discharge tube having an envelope closed at one end by a stem comprising a flat header, a tubular thimble extending through and projecting outwardly from the header, an exhaust tube extending through said thimble, and V 3 jecting beyond the outer end of said exhaust tube to protect said exhaust tube.

4. A stem for an electric discharge tube comprising a glass disc header, a tubular metal thimble embedded in and extending through said header With its uter end projecting from the outer side of said header, an exhaust tube extending through said thimble, and a tubular metal shield secured to the proiectingnwend oi aid thimble and surrounding and covering said exhaust tube.

5. A stem for an electric discharge tube comprising a flat header of glass; an exhaust tube projecting from the outer'sidaof said header, a

tubular metal thimble embedded in and p'roje'ot-"' ing from the outer side of "said-header and surrounding said exhaust tube, and a tubular metal hield telescoped over and securedIothe-Dlfljqcting end of said thimble and extending beyond the outer end of said exhaust tube.

file of this v r FQREIGN PATENTS Hum??? .:.-,t:; Date lid-292 Australia Nov. 12, 1941 552,753 Great Britain Apr. 22, 1943 

